What is the most common cause of postpartum hemorrhage (PPH)?

Uterine atony is recognized as the most common cause of postpartum hemorrhage (PPH) due to its prevalence in the immediate postpartum period. This condition occurs when the uterus fails to contract effectively after delivery, which is critical for controlling bleeding from the placental site. Following childbirth, it is the normal and expected response for the uterus to contract firmly and expel any remaining placental tissue. If this contraction does not happen adequately, the blood vessels that were supplying the placenta can remain open, leading to significant blood loss.

Multiple risk factors contribute to uterine atony, including prolonged labor, over-distension of the uterus from multiple gestations (twins or more), the use of medications that relax the uterus (such as magnesium sulfate), and previous instances of atony. These factors make uterine atony a primary concern in the immediate management of patients postpartum.

In contrast, while cervical lacerations, sulcus tears, and episiotomy extensions can result in bleeding, they do not account for the majority of postpartum hemorrhage cases. Uterine atony stands out as a systemic issue that directly affects uterine function instead of localized injuries and is often the first consideration in cases of significant postpartum bleeding. Understanding the significance of uter